Tag: naturalist

Natural selectionis the differential survival and reproduction of individuals due to differences inphenotype; it is a key mechanism ofevolution. The term “natural selection” was popularised byCharles Darwin, who intended it to be compared with artificial selection, now more commonly referred to asselective breeding.

Variationexists within allpopulationsoforganisms. This occurs partly because randommutationsarise in thegenomeof an individual organism, and these mutations can be passed tooffspring. Throughout the individuals’ lives, their genomes interact with their environments to cause variations intraits. (The environment of a genome includes the molecular biology in thecell, other cells, other individuals, populations,species, as well as the abiotic environment.) Individuals with certain variants of the trait may survive and reproduce more than individuals with other, less successful, variants. Therefore, the population evolves. Factors that affect reproductive success are also important, an issue that Darwin developed in his ideas onsexual selection, which was redefined as being included in natural selection in the 1930s when biologists considered it not to be very important,andfecundity selection, for example.

Natural selection acts on the phenotype, or the observable characteristics of an organism, but thegenetic(heritable) basis of any phenotype that gives a reproductive advantage may become more common in a population (seeallele frequency). Over time, this process can result in populations that specialise for particularecological niches(microevolution) and may eventually result in the emergence of new species(macroevolution). In other words, natural selection is an important process (though not the only process) by which evolution takes place within a population of organisms. Natural selection can be contrasted with artificial selection, in which humansintentionally choose specific traits (although they may not always get what they want). In natural selection there is no intentional choice. In other words, artificial selection isteleologicaland natural selection is not teleological.